A goal of roadway safety is to provide a forgiving roadway and adjacent roadside for errant motorists. Guardrails are employed along a roadside to accomplish multiple tasks. Upon vehicle impact, a guardrail must react as a brake and shock absorber to dissipate the kinetic energy of the vehicle. Subsequently, the guardrail acts as a mechanical guide to redirect the vehicle away from hazards during deceleration and to prevent the vehicle from leaving the road, becoming airborne or rebounding into traveled lanes of traffic.
For many years, a standard heavy gauge metal guardrail known as the "W-beam" has been used on the nation's roadways to accomplish these tasks and others. Named after its characteristic shape, the "W-beam" is typically anchored to the ground using posts made of metal, wood or a combination of both.
Recently, there has been a vigorous effort to raise the performance standards which guardrails must satisfy. Increasingly stringent testing criteria have uncovered serious deficiencies in the performance of standard "W-beam" guardrails. Accordingly, recent efforts have focused on development of a new guardrail system that will accomplish safety goals more effectively.
One such design included a deeper and wider "W-beam." However, this change in geometry required a significant increase in hardware to attach adjacent sections of the beam at the splice. Alternative systems have not gained widespread industry acceptance.